Astragalus sinaloae Barneby, Mem.

Castillón, Eduardo Estrada, Quintanilla, José Ángel Villarreal, Delgado-Salinas, Alfonso & Rebman, Jon P., 2023, The genus Astragalus (Leguminosae: Papilionoideae: Galegeae) in Mexico, Phytotaxa 586 (1), pp. 1921-1935 : 1921-1935

90. Astragalus sinaloae Barneby, Mem. New York Bot. Gard. 13(1): 450. 1964

Type:— MEXICO, Sinaloa, Ocurahui, Sierra Surotato , 1–10 September 1941, H. S. Gentry 6283 (holotype: MICH 1107124 digital image; isotype: GH 00059441 digital image!, ARIZ-BOT-0004003 digital image, NY 00005850 !) .

Perennial. Stems up to 47 cm long, decumbent, minute strigose, trichomes very short, up to 0.2 mm long. Stipules 1.2–2.7 mm long, semi-clasping, or the upper ones somewhat free, triangular to lanceolate, not connate. Leaves 2–5.5 cm long, leaflets 13–17, 3–9 mm long, oblong, elliptic or obovate, distally entire or notched, adaxially glabrate. Peduncles 2–9 cm long; the racemes 2–5 cm long, commonly dense, flowers 15–33. Flowers whitish, turning yellowish when drying; the calyx 2.6–2.7 × 1.8–2 mm, minute pubescent, the tube 1.8–2.1 mm long, the teeth 0.7–0.8 mm long, triangular to subulate; the banner 5.2–5.3 × 3.3 mm, obovate, recurved, distally shallowly retuse; the wings 4.9–5.2 × 1.4 mm, the claw 2.1–2.2 mm long, the blade 2.8–3.6 mm long, oblong to obovate, distally oblique; the keel 5.1–5.3 × 1.9 mm, the claw 2.1–2.3 mm long, the blade 3–3.3 mm long, almost elliptic, distally oblique. Pod 11–15 × 2–2.5 mm, deflexed, shortly stipitate (stipe 0.5–0.9 mm long), triquetrous, linear, narrowed in both ends, ventrally compressed and carinated, dorsally sulcate, lateral faces straight, the angles narrows and obtuse, the valves strigose, the trichomes white, very rarely some black scattered ones mixed, papery, ochre, reticulate, septum complete, the pod thence bilocular; ovules 10–12; seeds mitten shaped, brown, light-brown, somewhat opaque.

Distribution:— Northwestern Mexico, at three separated localities; southern Sonora (Álamos); central (Badiraguato) and southern (Concordia) Sinaloa. Note that these last two localities are in close proximity to southwestern Chihuahua and southwestern Durango respectively ( Fig. 25 ).

Habitat:— Volcanic, reddish and clayey soils; humid or sub-humid ravines; associated with conifer forests; oakpine forest; associated with with madrone; cloud forest; areas with walnut and pecan; 1400–2160 m.

Comments:— The mountainous areas where A. sinaloae is distributed is home to at least eight other species of Astragalus . Of these species, only A. sinaloae and A. ervoides possess whitish or yellowish (banner or their veins sometimes slightly with lilac tones and the apex of the keel purple) petals and stipitate triquetrous pods and. A. ervoides can be differentiated due to the ovary and pod being glabrate, whereas in A. sinaloae both are pubescent.

Specimens examined:— DURANGO: 2 September 1997, Sierra Madre Occidental: Los Mangles Cañon, 7.5 km N (“ E ”) of the Sinaloa line along Hwy 40 ( Mazatlan-Durango Hwy ) ca. 1.2 km S of Revolcaderos, A. C. Sanders 21244, F. M. Roberts, P. Mackay, T. Tomas, M. Egger, S. Eliason ( NY) ; 27 September 1973, Along Mexico Highway 40, about 97 miles east of Mazatlan and 105 miles west of Durango, along El Espinazo del Diablo, 4.1 miles west of Las Blancos and 20.2 miles east of El Palmito , 15.1 miles west of La Ciudad, Sierra Madre Occidental, J. L. Reveal 3574 ( MEXU, NY) ; 17 August 1970, 56 miles SW of El Salto , C. D. Johnson 110-70 ( MEXU, NY) . SINALOA: 12 August 1974, Steep slopes of Barranca 3 km NE of El Palmito , D. E. Breedlove 36461 ( MEXU, NY) ; 1 October 1971, 5.5 mi. O de El Palmito a unos 50 m. en el lado cuesta abajo de la autopista 40, donde se extiende un camino de tierra en una pequeña cresta, R. Spellenberg 2719 ( NY, ENCB) , aproximadamente ¼ mi. O de El Palmito a lo largo de la antigua carretera de registro detrás de la estación de bomberos de Rancho Liebre, R. Spellenberg 2722 ( ENCB, NY) , proximadamente ¼ mi. O de El Palmito a lo largo de la antigua carretera de registro detrás de la estación de bomberos de Rancho Liebre, R. Spellenberg 2723 ( ENCB, NY) D. Jackson, D. Martin ( NY) ; 2 October 1970, 3 miles N of Los Ornos along road to Ocurahui, D. E. Breedlove 18330 ( NY) ; 1 September 1941 / 10 September 1941, Ocurahui, Sierra Surotato. Alt. 6000–7000 ft, H. S. Gentry 6283 ( NY) ; 11 September 1979, Concordia along Mexican Highway 40, 6–8 km SE of El Palmito D. E. Breedlove 43852 ( MEXU) . SONORA: 20 August 1994, Sierra de Alamos, ca. 5 km SW of Alamos along the trail from La Huerta to Cerro Aduana, V. W. Steinmann 94-79, M. Fishbein, A. Martin ( MEXU, NY) .

Figures

FIGURE 25. Map showing the distribution of Astragalus sanguineus, A. scalaris, A. scutaneus, A. sinaloae, and A. spellenbergii in Mexico.